KR100679704B1 - Manufacturing method of Nanogap or nanoFET for molecular device and bio-sensor - Google Patents

Abstract

The present invention relates to a method for manufacturing a nanogap and a nanofield effect transistor (nanoFET) for a molecular device or a bio-sensor, and more specifically, high reproducibility using a thin film of a molecule or its size. The present invention relates to a method of manufacturing a nanogap.

Method of manufacturing a nanogap (nanogap) according to the present invention, (a) sequentially forming a silicon substrate, an insulating film, a first metal layer and a hard mask; (b) etching the first metal layer using the mask pattern as a mask; (c) forming a self-assembled monolayer (SAM) on the side of the first metal layer to form a nanogap on the silicon substrate; (d) depositing a metal to form a second metal layer on the silicon substrate; (e) etching the hard mask formed in step (a) to remove the metal deposited on the hard mask by using lift-off fixing; And (f) etching the SAM formed in step (c) to form a nanogap.

Molecular device, Molecular device, bio-sensor, nanogap, nanoFET, SAM, ALD

Description

Manufacturing method of nanogap or nanoFET for molecular device and bio-sensor

1 is a cross-sectional view sequentially showing a method of manufacturing a horizontal nanogap for a biosensor according to an embodiment of the present invention.

2 is a cross-sectional view sequentially showing a method of manufacturing a vertical nanogap for a biosensor according to an embodiment of the present invention.

3 is a cross-sectional view sequentially illustrating a method of manufacturing a vertical nanogap for a biosensor according to another embodiment of the present invention.

4 is a cross-sectional view sequentially illustrating a method of fabricating a molecular device using a vertical nanogap and a molecule as a channel according to another embodiment of the present invention.

***** Description of the symbols for the main parts of the drawings *****

101, 201, 301, 401: silicon substrate 102, 202, 302, 402: insulating film

103, 203, 303, 404: first Au layer 104, 206, 306, 408: hard mask

105, 204: Self-Assembled Monolayer 304, 405: Al2O3 layer

106, 205, 305, 406: Second Au layer 403, 407: Si3N4 layer

409: SiO 2 layer (side-wall) 410: gate material

411: channel molecular layer 101-1: doped back-gate

The present invention relates to a method for manufacturing a nanogap and a nano field effect transistor (nanoFET) for a molecular device or a bio-sensor, and more particularly, to a thin film of a molecule or its size. It relates to a production method such as nanogap (nanogap) with high reproducibility.

Metal nanogaps, with metal plates on both sides with nanometer-sized gaps between them, are useful for the production of molecular devices and biosensors.

As semiconductor devices continue to develop, technology has been continuously reduced in size, and device performance has been improved.

However, due to the technical problems of lithography used in semiconductor processes (wavelength of light source, light scattering, NA limit of lens, absence of photoresist), device size miniaturization has reached its limit.

Molecular devices have been proposed to overcome these limitations of semiconductor device miniaturization.

Molecular devices are a new concept of devices that use molecules as channels.

In order to implement such a molecular device, a gap corresponding to the length of a molecule must exist between two metal plates serving as source / drain of a conventional field effect transistor.

However, as mentioned above, the formation of molecular size gaps using conventional lithography faces technical limitations.

Biosensors are detectors that detect specific molecules that make up organisms, such as enzymes and antibodies.

There is a method of detecting by chemical, optical, and electrical methods, among which the electrical detection method has the advantage that it can be quickly detected in a small amount.

By forming a highly integrated sensor using the conventional silicon process, it is also possible to produce a portable sensor at a low price by mass producing a small sensor.

After injecting a solution containing biomaterials between the nanogaps, a specific material can be detected by changing the electrical properties across the nanogaps. nanogap) can be used as an electrical sensor.

At this time, the smaller the gap size of the nanogap (nanogap), the more sensitive it is possible to detect more effectively.

However, forming gaps of several nanometers or less using lithography used in the conventional silicon process has technical limitations such as wavelength of light source used and scattering of light, and also nanogap using lithography ( The formation of nanogaps requires a complex process and the reproducibility decreases as the gap size becomes smaller, making it difficult to fabricate a gap of several nanometers required for high performance biosensors.

In order to implement molecular devices or biosensors, it is essential to create nanogaps of several nanometers in size through new methods.

An object of the present invention for solving the above problems, after forming a metal layer and Al ₂ O ₃ layer through a Self-Assembled Monolayer (SAM) or ALD (Atomic Layer Deposition) process on a silicon substrate SAM or Al ₂ The present invention provides a method of fabricating nanogap of several nanometers by etching or partially etching an O ₃ layer.

In addition, another object of the present invention is to manufacture a nano-field effect transistor (nanoFET), which is a molecular device to replace the existing high-density, high-performance biosensor and the conventional device by using a nanogap manufacturing method described above in a simple method To provide a way.

Method of manufacturing a nanogap (nanogap) for a biosensor according to an embodiment of the present invention, (a) sequentially forming a silicon substrate, an insulating film, a first metal layer and a hard mask; (b) etching the first metal layer using the mask pattern as a mask; (c) forming a self-assembled monolayer (SAM) on the side of the first metal layer to form a nanogap on the silicon substrate; (d) depositing a metal to form a second metal layer on the silicon substrate; (e) etching the hard mask formed in step (a) to remove the metal deposited on the hard mask by using lift-off fixing; And (f) etching the SAM formed in step (c) to form a nanogap.

Here, the metal used for the first and second metal layers is preferably gold (Au).

The first and second metal layers may be formed using any one of a vapor deposition, sputtering, or pulsed laser deposition (PLD) process.

In addition, the manufacturing method of the vertical nanogap (nanogap) according to an embodiment of the present invention, (a) sequentially forming a silicon substrate, an insulating film and the first metal layer; (b) sequentially forming a SAM, a second metal layer, and a hard mask to form a nanogap on the silicon substrate; (c) etching the second metal layer, the SAM, and the first metal layer using the mask pattern as a mask; (d) etching the hard mask formed in step (b) to secure a pattern on which the SAM is to be formed; (e) partially etching the SAM to form a nanogap.

Here, the metal used for the first and second metal layers is preferably gold (Au).

In addition, the manufacturing method of the vertical nanogap (nanogap) according to another embodiment of the present invention, (a) sequentially forming a silicon substrate, an insulating film and the first metal layer; (b) sequentially forming a dielectric, a second metal layer, and a hard mask to form a nanogap on the silicon substrate; (c) etching the second metal layer, the dielectric, and the first metal layer using the hard mask as a mask; And (d) partially etching the dielectric formed in the step (b) to form a nanogap.

Here, it is preferable to use gold (Au) as the metal of the first and second metal layers.

Here, the dielectric of step (b) is preferably Al ₂ O ₃ .

In addition, the manufacturing method of the vertical nanogap (nanogap) according to another embodiment of the present invention, (a) sequentially forming a silicon substrate, an insulating film, a first silicon nitride film and a first metal layer; (b) sequentially forming a first dielectric, a second metal layer, a second silicon nitride film, and a hard mask on the silicon substrate to form a nanogap; (c) etching the second silicon nitride film, the second metal layer, the first dielectric, the first metal layer, and the first silicon nitride film using the hard mask as a mask; (d) depositing a second dielectric layer capable of film deposition and bimodal angle on the silicon substrate; (e) forming a gate oxide layer on the second dielectric layer by using an etch-back process; (f) depositing a gate material on the pattern formed on the silicon substrate; (g) forming a gate using the photoresist pattern as a mask with the gate material deposited in step (f); (h) etching the first dielectric layer formed in step (b) to form a vertical nanogap; And (i) forming a molecular layer having a length equal to the width of the nanogap in the vertical nanogap formed in step (h).

Here, it is preferable to use gold (Au) as the metal of the first and second metal layers.

Here, the dielectric of step (b) is preferably Al ₂ O ₃ .

Here, the dielectric of step (d) is preferably SiO ₂ .

Hereinafter, with reference to the accompanying drawings a preferred embodiment of a method of manufacturing a nanogap (nanogap) or nano-field effect transistor (nanoFET) for a molecular device or a biosensor according to the present invention will be described in detail.

1 is a process cross-sectional view sequentially showing a method of manufacturing a horizontal nanogap (nanogap) for a biosensor according to an embodiment of the present invention.

As shown, a horizontal nanogap corresponding to the length of SAM is formed by forming a first Au layer (metal layer) on a silicon substrate and separating the second Au layer from the first Au layer using SAM. To form.

First, a silicon substrate 101, a back-gate thin film 101-1 using doping, an insulating film 102, a first Au layer 103, and a hard mask 104 are sequentially formed (100A).

The hard mask 104 may be made of a material that is not etched after the first Au layer anisotropic etching.

Next, the first Au layer 103 is anisotropically etched using the hard mask 104 pattern as a mask to form a pattern to be one electrode of a horizontal nanogap in a subsequent process (100B).

Next, in order to form a gap between the first Au layer 103 and the second Au layer 106, a SAM 105 is formed on the side of the first Au layer 103 (100C).

Here, it is preferable to select and use SAM having good adhesion with Au.

Next, to form another electrode of the horizontal nanogap (nanogap), the second Au layer 106 is formed on the etch-exposed insulating film 102 (100D).

Here, the second Au layer 106 is not formed on the SAM 105 formed on the side surface of the first Au layer 103 due to the hard mask 104.

Next, by etching the hard mask 104, a pattern in which the SAM 105 is formed between two electrodes is obtained.

The second Au layer 106 formed on the hard mask 104 is simultaneously etched (100E) while etching the hard mask.

Next, the SAM 105 formed between the first Au layer 103 and the second Au layer 106 is etched (100F).

In this case, in order to use the horizontal nanogap (nanogap) as a nanofield effect transistor (nanoFET), the SAM 105 serving as a channel molecular layer should not be removed, and thus the present process 100F is not necessary.

By this process, it is possible to fabricate a horizontal nagap or a nanofield effect transistor (nanoFET) for a biosensor according to an embodiment of the present invention, and the width of the nanogap depending on the length of the SAM. It is possible to adjust.

By controlling the chain length of the SAM (atomic unit), it is possible to realize a fluid nanogap width having an atomic size accuracy depending on the size of the biomaterial to be detected.

2 is a cross-sectional view sequentially illustrating a method of manufacturing a vertical nanogap for a biosensor according to an embodiment of the present invention.

As shown, a vertical Au nanogap corresponding to the length of the SAM is formed by forming a first Au layer on the silicon substrate and separating the second Au layer from the first Au layer using SAM. do.

The silicon substrate 201, the insulating film 202, the first Au layer 203, the SAM 204, and the second Au layer 205 are sequentially formed (200A).

Next, a hard mask 206 is formed on the second Au layer 205 (200B).

The hard mask 206 is for etching the first Au layer 203, the SAM 204, and the second Au layer 205 in a subsequent process, so that the first Au layer 203, the SAM 204, and the second Au layer 205 are etched. The anisotropic etching of the Au layer 205 is formed sufficiently thick with a material that is not etched.

Next, the first Au layer 203, the SAM 204, and the second Au layer 205 are anisotropically etched using the hard mask 206 pattern as a mask to be a vertical nanogap in a subsequent process. Form (200C).

Next, by etching the hard mask 206, a pattern in which the SAM 204 is formed between two electrodes is obtained (200D).

Next, the SAM 204 formed between the first Au layer 203 and the second Au layer 205 is partially etched to form a portion that becomes a nanogap (200E).

By this process, it is possible to manufacture a vertical nanogap (nanogap) for the biosensor according to an embodiment of the present invention and it is possible to adjust the width of the nanogap (nanogap) according to the length of the SAM.

By controlling the chain length of the SAM (atomic unit), it is possible to realize a fluid nanogap width having an atomic size accuracy depending on the size of the biomaterial to be detected.

3 is a cross-sectional view sequentially illustrating a method of manufacturing a vertical nanogap for a biosensor according to another exemplary embodiment of the present invention.

Vertical nanogap forming the first 1 Au layer on a silicon substrate and that the thickness of the Al ₂ O ₃ formed by separating the first 2 Au layer by using the Al ₂ O ₃ and claim 1 Au layer as shown ( nanogap).

The silicon substrate 301, the insulating film 302, the first Au layer 303, the Al ₂ O ₃ layer 304, and the second Au layer 305 are sequentially formed (300A).

Here, the Al ₂ O ₃ layer 304 is formed using ALD (Atomic Layer Deposition).

Here, the use of ALD makes it possible to form layers on an atomic scale.

Next, a hard mask 306 is formed on the second Au layer 305 (300B).

Here, since the hard mask 306 is for etching the first Au layer 303, the Al ₂ O ₃ layer 304, and the second Au layer 305 in a subsequent process, the first Au layer 303 and Al may be etched. _{The 2} O ₃ layer 304 and the second Au layer 305 are formed sufficiently thick with a material that is not etched during anisotropic etching.

Next, the first Au layer 303, the Al ₂ O ₃ layer 304, and the second Au layer 305 are anisotropically etched using the hard mask 306 pattern as a mask, and a vertical nanogap in a subsequent process. A pattern to be formed) is formed (300C).

Next, by etching the hard mask 306, a pattern in which an Al ₂ O ₃ layer 304 is formed between two electrodes is obtained (300D).

Next, the Al ₂ O ₃ layer 304 formed between the first Au layer 303 and the second Au layer 305 is partially etched to form a portion that becomes a nanogap (300E).

By this process, it is possible to manufacture a vertical nanogap (nanogap) for the biosensor according to another embodiment of the present invention, and according to the thickness of the Al ₂ O ₃ formed through ALD sub-nanometer (sub- It is possible to control the width of the nanogap with nanometer accuracy.

That is, it is possible to obtain a thin film of various thickness by artificially adjusting the thickness through various conditions (gas pressure, process time, etc.) in the ALD process.

4 is a cross-sectional view sequentially illustrating a method of fabricating a molecular device using a vertical nanogap and a molecule as a gate dielectric layer for a molecular device according to another embodiment of the present invention.

Vertical nano-gap, forming the first 1 Au layer on a silicon substrate and that the thickness of the Al ₂ O ₃ formed by separating the first 2 Au layer and a 1 Au layer by using the Al ₂ O ₃ as shown ( nanogap).

After that, a molecule having a length equal to a gap size serving as a gate dielectric layer is formed in a vertical nanogap formed to implement a nanofield effect transistor (nanoFET).

Silicon substrate 401, insulating film 402, first Si ₃ N ₄ layer 403, first Au layer 404, Al ₂ O ₃ layer 405, second Au layer 406, second Si _The 3N ₄ layer 407 and the hard mask 408 are sequentially formed (400A).

Here, the Al ₂ O ₃ layer 405 is formed using ALD.

Here, the use of ALD makes it possible to form layers on an atomic scale.

In addition, the hard mask 408 may further include a first Si ₃ N ₄ layer 403, a first Au layer 404, an Al ₂ O ₃ layer 405, a second Au layer 406, and a second Si in a subsequent process. _For etching the ₃ N ₄ layer 407, the first Si ₃ N ₄ layer 403, the first Au layer 404, Al ₂ O ₃ layer 405, the second Au layer 406, The 2 Si ₃ N ₄ layer 407 is formed sufficiently thick with a material that is not etched during anisotropic etching.

Next, the first Si ₃ N ₄ layer 403, the first Au layer 404, the Al ₂ O ₃ layer 405, the second Au layer 406, and the first mask are formed using the hard mask 408 as a mask. After anisotropically etching the 2 Si ₃ N ₄ layer 407, the hard mask 408 is removed (400B).

Next, a SiO ₂ layer 409 is deposited on the pattern.

Here, the SiO ₂ layer 409 is to form a SiO ₂ side-wall between the gate and Au layer to be formed in a later process (400C).

Next, the SiO ₂ layer 409 is etched back to form two side-walls at the portion where the gate is to be formed (400D).

Next, after the gate material 410 is deposited, a gate is formed using a photoresist pattern, and an Al ₂ O ₃ layer 405 is etched to form a nanogap in which a molecular layer is to be formed (400E). .

Next, the molecular layer 411 having the same length as the width of the nanogap (nanogap) resulting from the etching of the Al ₂ O ₃ layer 405 is formed (400F).

By this process, it is possible to manufacture a vertical nanogap (nanogap) for the molecular device according to another embodiment of the present invention, and according to the thickness of the Al ₂ O ₃ formed through the ALD sub-nanometer ( The accuracy of the sub-nanometer size makes it possible to control the width of the nanogap.

In addition, by forming a molecular layer in the nanogap (nanogap) prepared in the above process it is possible to manufacture a nano-nano field effect transistor (FET).

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modified forms derived from the equivalent concept should be construed as being included in the scope of the present invention.

Through the nanogap and nanofield effect transistor (nanoFET) manufacturing method for a molecular device or a biosensor according to the present invention, a highly integrated nanogap structure can be manufactured through a simple and reproducible process.

In addition, by selecting the proper SAM and ALD process, it is possible to fabricate nanogaps of several nanometers that are difficult to implement in existing processes.

In addition, various types of SAM and ALD processes may be used to fabricate nanogaps of a size suitable for a biomaterial to be detected with an accuracy of sub-nanometer size.

In addition, the present invention is a very practical technology using the current semiconductor process and nanogap (nanogap) manufacturing technology that can replace the existing lithography showing a limitation in scaling, so the ripple effect is large throughout the biosensor or molecular device industry.

Claims (16)

(a) sequentially forming a silicon substrate, an insulating film, a first metal layer, and a hard mask; (b) etching the first metal layer using the mask pattern as a mask; (c) forming a self-assembled monolayer (SAM) on the side of the first metal layer to form a nanogap on the silicon substrate; (d) depositing a metal to form a second metal layer on the silicon substrate; (e) etching the hard mask formed in step (a) to remove the metal deposited on the hard mask by using lift-off fixing; And (f) etching the SAM formed in step (c) to form a nanogap; Including, nanogap fabrication method for a biosensor. The method of claim 1, The metal of the first and second metal layer is gold (Au), nanogap fabrication method for a biosensor. The method of claim 1, In the step (a) and (d), Forming the first metal layer and the second metal layer is formed using any one of a vapor deposition, sputtering or PLD (Pulsed Laser Deposition) process, a horizontal nanogap manufacturing method for a biosensor. delete (a) sequentially forming a silicon substrate, an insulating film, and a first metal layer; (b) sequentially forming a SAM, a second metal layer, and a hard mask to form a nanogap on the silicon substrate; (c) etching the second metal layer, the SAM, and the first metal layer using the mask pattern as a mask; (d) etching the hard mask formed in step (b) to secure a pattern on which the SAM is to be formed; (e) partially etching the SAM to form a nanogap; Vertical nanogap fabrication method for a biosensor comprising a. The method of claim 5, The metal of the first and the second metal layer is gold (Au), a vertical nanogap manufacturing method for a biosensor. delete (a) sequentially forming a silicon substrate, an insulating film, and a first metal layer; (b) sequentially forming a dielectric, a second metal layer, and a hard mask to form a nanogap on the silicon substrate; (c) etching the second metal layer, the dielectric, and the first metal layer using the hard mask as a mask; And (d) partially etching the dielectric formed in the step (b) to form a nanogap; Including, the vertical nanogap fabrication method for a biosensor. The method of claim 8, The metal of the first and the second metal layer is gold (Au), a vertical nanogap manufacturing method for a biosensor. The method of claim 8, The dielectric of step (b) is Al ₂ O ₃ , a vertical nanogap fabrication method for a biosensor. delete (a) sequentially forming a silicon substrate, an insulating film, a first silicon nitride film, and a first metal layer; (b) sequentially forming a first dielectric, a second metal layer, a second silicon nitride film, and a hard mask on the silicon substrate to form a nanogap; (c) etching the second silicon nitride film, the second metal layer, the first dielectric, the first metal layer, and the first silicon nitride film using the hard mask as a mask; (d) depositing a second dielectric layer capable of film deposition and bimodal angle on the silicon substrate; (e) forming a gate oxide layer on the second dielectric layer by using an etch-back process; (f) depositing a gate material on the pattern formed on the silicon substrate; (g) forming a gate using the photoresist pattern as a mask with the gate material deposited in step (f); (h) etching the first dielectric layer formed in step (b) to form a vertical nanogap; And (i) forming a molecular layer having a length equal to the width of the nanogap in the vertical nanogap formed in step (h); A nano field effect transistor (nanoFET) manufacturing method for a molecular device using a vertical nanogap, including. The method of claim 12, The metal of the first and second metal layer is gold (Au), a nano-field effect transistor manufacturing method for a molecular device using a vertical nanogap. The method of claim 12, In (b), the first dielectric is Al ₂ O ₃ , a nano-field effect transistor manufacturing method for a molecular device using a vertical nanogap. The method of claim 12, In (d), the second dielectric is SiO ₂ , wherein the nano-field effect transistor for a molecular device using a vertical nanogap. delete

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